Looking at grand final sides from a few years ago, you could make a fair guess.
2008 (the oldest of these guys are now 26):
Raiders:
Dugan
Low
Croker
Vidot
Waddell
Fensom
Carney (Justin)
Plus Mick Picker, Jarrad Kennedy and Nick Skinner played a couple of games.
Broncos:
Hoffman
Kahu
Hunt
McGuire
McCullough
Dodds
Glenn
Lui (Dunamis)
Will Tupou played a few games for the Cowboys and Jharal Yow Yeh played for Australia.
2009 (no older than 25 now):
Storm:
Widdop
O'Neill
Duffie
Bromwich
Rochow
McLean
Proctor
Sam Joe, Dane Chisholm, Luke Kelly and Billy Rogers all played a few massive NRL games.
Tigers:
Lui (Robert)
Fifita (Andrew)
Woods
Jake Mullaney, Simon Dwyer, Jason Schirnack and David Fifita have all played some first grade.
2010 (no older than 24):
Bunnies:
Mansour
Reynolds
Starling
Peats
James Roberts, Junior Vaivai and Kane Morgan have all played some NRL.
Warriors:
Fisiiahi
Feki
Johnson
Taylor
Omar Slaimankhel, Siuatonga Likiliki, Carlos Tuimavave, Neccrom Areai'iti, Mark Ioane, Matt Robinson, Sebastine Ikahihifo, Nafe Seluini, Charlie Gubb and Sam Lousi have all played some first grade.
A lot of these guys that have dabbled in first grade are still contracted to NRL clubs as backup players, especially the 'class of 2010'. It's not really until these guys turn about 24 that they decide to throw in the towel if they haven't already made it.
Certainly, the '08 Raiders and Broncos, and the '09 Storm produced plenty of first graders. There's a few possible reasons why less first graders might have been produced by more recent NYC grand final teams, including the fact that many of the players aren't yet near their peak, and the likelihood that some clubs were much better at junior development (#'academy') and other clubs have since caught up.
There's also the fact that I've only looked at six teams over three years. A fairly small sample, as I'm sure you'll all agree.
